There are two common techniques used for forming intraocular lenses. One technique is molding, where an optical polymeric material is formed into a desired shape having a predetermined dioptic power. These lenses are available in steps of about 0.5 diopter power. A problem with the molding technique is it is a very expensive way to make a customized lens, and thus for most patients, only an approximate approach to clear vision can be obtained.
The other technique used is lathing and milling, where a disc shaped blank is ground to a desired shape. Due to the properties of the materials used for intraocular lenses, it is preferable to machine lenses at a reduced temperature such as −10° F. A problem with lathing and milling is that optical properties of a lens at −10° F. may be different than the optical properties of the lens at body temperature, and thus such a lens only approximates optimal vision. In addition, as the lens warms it absorbs moisture and dimensions of the lens may change, thus altering the diopter power of the lens.
Accordingly, there is a need for a system and method for forming intraocular lenses that overcomes the disadvantages of prior art manufacturing techniques, and also allows for customization of lenses to provide multiple corrective features to approach optimum vision such as toricity, asphericity, multifocality, and the correction of higher order optical aberrations (HOAs).